February 26, 1996 in Nation/World

Lost In Space: $440 Million Satellite’s Tether Breaks A Costly Failure For Nasa And The Italian Space Agency

William Harwood Washington Post
 

A $440 million science satellite was lost in space Sunday night when a slender tether holding it to the shuttle Columbia suddenly snapped, sending the small instrument package sailing into oblivion in a costly failure for NASA and the Italian Space Agency.

“The tether has broken at the boom!” astronaut Jeffrey Hoffman suddenly exclaimed when the cable broke. “The tether has broken. It is going away from us. Get it on the TV, Claude, please get it on the TV! The tether has broken.”

Astronaut Claude Nicollier quickly aimed the shuttle’s television cameras as the receding satellite to document its departure. In stark, black-and-white footage, the satellite could be seen slowly sinking in the black night of space, trailing 12 miles of jumbled, now-useless tether in its wake.

Columbia and its seven-man crew were not in any danger from the incident. The cable broke inside a telescoping 39-foot launching boom extending out of the shuttle’s cargo bay like a giant fishing rod. About 30 feet of tether remained inside the boom, but the rest pulled free with the satellite.

Putting their disappointment aside, the astronauts and flight controllers worked to inspect the boom to make sure the remaining cable would not prevent the tower’s retraction later. The boom can be jettisoned if necessary.

The astronauts were in the process of unreeling the Italian Tethered Satellite 12.5 miles into space when the tether snapped.

The idea was to demonstrate a novel technique for generating electrical power using the tether’s passage through Earth’s magnetic field and electrically charged ionosphere. Other applications included futuristic methods for raising or lowering a satellite’s orbit without using rocket power.

The deployment had proceeded like clockwork from the point the satellite was released at 3:45 p.m. Sunday, and excited scientists watched their instruments eagerly as electrons began flowing through the tether exactly as planned.

“The tether is not straight. It makes a huge bow,” Hoffman observed at one point. “It goes out toward the nose of the shuttle and then makes a huge curving arc to come back to the satellite. It’s quite remarkable. When the sun rises, the satellite is the brightest star in the sky.”

“That’s awesome,” replied astronaut David Wolf in Houston. “We are really pushing out tether right now.”

“Yeah, we’re pushing out lots of tether and we’re pulling down a lot of electrons,” Hoffman replied.

“Sitting close to 1,600 volts,” Wolf said. “And that’s at 420 milliamps, Jeff.”

But suddenly, with the satellite about 12 miles out, the tether snapped without warning. The satellite was propelled away at nearly 100 mph relative to the shuttle, almost as if the tether had been a rubber band.

The failure Sunday was especially disheartening because of the project’s history.

In 1992, the crew of the shuttle Atlantis - including four members of Columbia’s current crew - failed to fully deploy the satellite when the tether jammed after just 843 feet of cable had played out.


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